1. Field of Art
The present invention relates to a plasma reactor used for treating surface of a substrate or depositing one or more layers of materials on a substrate.
2. Description of the Related Art
Plasma is partially ionized gas consisting of large concentrations of excited atomic, molecular, ionic, and free-radical species. The radicals generated by plasma can be used for various purposes, including (i) chemically or physically modifying the characteristics of a surface of a substrate by exposing the surface to the reactive species or radicals, (ii) performing chemical vapor deposition (CVD) by causing reaction of the reactive species or radicals and source precursor in a vacuum chamber, and (iii) performing atomic layer deposition (ALD) by exposing a substrate adsorbed with source precursor molecules to the reactive species or radicals.
There are two types of plasma reactors: (i) a direct plasma reactor, and (ii) a remote plasma reactor. The direct plasma reactor generates plasma that comes into contact directly with the substrate. The direct plasma reactor may generate energetic particles (e.g., free radicals, electrons and ions) and radiation that directly contact the substrate. Such contact may cause damage to the surface of the substrate and also disassociate source precursor molecules adsorbed in the substrate. Hence, the direct plasma reactor has limited use in fabrication of semiconductor devices or organic light emitting diode (OLED) devices.
A remote plasma device generates plasma at a location remote from the substrate. When generating the plasma, other undesirable irradiation of electrons, ultraviolet ray or ions may also result from the plasma. The substrate may be exposed to such irradiation and cause damage to the substrate or make undesirable changes to the properties of the substrate.